defined.js

export function getStreak(answers) {
  let streak = 0;
  for (const answer of answers) {
    if (!answer.correct) {
      break;
    }

    streak++;
  }
  
  // even if there are no answers, streak is still a number
  return streak;
}

undefined.js

let value;
this.props.options.forEach(option => {
  const path = this.props.useLink ? withPrefix(option.value) : option.value;
  const isActive = option.matchRegex
    ? option.matchRegex.test(path)
    : this.props.isPathActive(path);
  if (isActive) {
    value = option.value;
  }

  if (option.subpages) {
    option.subpages.forEach(subpage => {
      if (this.props.isPathActive(subpage.value)) {
        value = option.value;
      }
    });
  }
});

// use value down here and change the UI in some way if it's falsey (undefined)